High quality chip, guarantee quality without false alarm Large detection range, 0-8 meters large detection range High-fidelity speakers, built-in 38 music, low consumption 150 meters distance, wireless reception, host position removable Multiple uses to meet different needs Can be used in hotels, hotels, shops, offices, homes, etc. Receiver operating voltage: 110-240V Transmitter operating voltage: 4.5V (3 batteries, 7 batteries) Receiver button: 1) Music: 38 music options, side music logo buttons to adjust 2) Volume: three-speed volume adjustment (high, medium, low) side volume indicator button to adjust 3) Can be set with sound and no sound (with sound: sound and indicator silent: indicator light) Working distance: up to 70 meters Transmitter sensing distance: 3-7 meters Receiver size: 76x80x33mm Transmitter size: 80x59x45mm Specifications: Product operation instructions: 1. Plug the receiver into the socket and turn on the detector battery cover to insert the battery. 2, the rotating bracket is stuck in the back of the detector 3. The detector switch is pushed to the ON position and waits for the self-test time of 10 seconds to enter the normal working state. Package Included: 1x receiver 1x transmitter 1x instruction manual Notes: Due to the difference between different monitors, the pictures may not reflect the actual color of the item. Compare the detail sizes with yours, please allow 1-3cm error, due to manual measurement. Please leaving a message before you give the bad feedback, if the products have some problems. Thanks for your understandings.